What is COB(Chip On Board)?

COB light source means that the chip is directly bonded and packaged on the entire substrate. That is, N chips are integrated on the inner substrate for packaging, and the LED chip is directly attached to the mirror metal substrate or ceramic substrate with high reflectivity.

COB technology is mostly used in low-power chips are difficult to produce high-wattage LED lights. By dispersing the heat of the chip, COB technology can improve light efficiency and reduce glare. Thanks to its high luminous flux density, COB produces evenly distributed light with little to no glare.

Under the premise of the same wattage, COB light fixtures are generally less expensive than SMD light fixtures. The COB light source eliminates the need for a bracket during the production process, which also reduces costs.

The COB light source is a high-power integrated surface light source. The light emitting area and shape size of the light source can be designed according to the shape and structure of the product. In markets, the COB size mainly includes 11mm, 17mm, 20mm, 23mm, 32mm, 42mm, and 60mm for different wattages. The wattage is generally larger than 3 watts.

Feature of COB LED Chips

Our LED lights are designed for electrical stability, scientific and reasonable circuit design, optical design, and heat dissipation design.
The use of heat sink technology ensures that the LED has an industry-leading heat lumen maintenance rate (95%). The lifetime is longer than 50000Hrs.
It is convenient for the secondary optical matching of the product and improves the lighting quality.
High color rendering, generally COB Chips RA more than 90.
Uniform luminescence, no spot, healthy, and environmentally friendly.
Simple installation, convenient use, reducing the difficulty of the lamp design, saving lamp production processing and subsequent maintenance costs.

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What is SMD(Surface Mounted Devices)?

SMD stands for Surface Mounted Devices. SMDs are components that are used in surface mount technology (SMT). With SMDs, there is only a single chip or a few chips on each light source.

The SMD light source emits divergent light. When forming an LED lamp, it is often used with a reflector. Generally, the power of a single light source is low.

This process is well-suited for high-power product creation with a large number of aluminum substrates. The currently available SMD LED chips are as follows:

What is the difference between COB and SMD chips?

1. The production process is different.

SMD: The LED chip is attached to the pad of the lamp bead holder with conductive glue and insulating glue, and then welded with the same conduction performance as the COB package. After passing the performance test, it is encapsulated with epoxy resin, then light is split, Cut, and taped, and transported to the screen factory and other processes.
COB: After the LED chip is soldered to the lamp bead on the PCB board, it is then tested for proper conductivity. If it meets the standards, it is then encapsulated with epoxy resin.

2. The luminous effect is different

SMD: The light-emitting surface of the SMD LED chip is non-uniform, causing glare.
COB: COB LED downlights offer several advantages over their SMD counterparts. COB LEDs have a larger viewing angle and are easier to adjust. さらに, COB LEDs produce no glare and have a uniform, round spots with no astigmatism or shadows. SMD LEDs, on the other hand, have bright spots in the middle of the light spot, halos on the outer edges, and uneven light spot transitions.

3. Packaging method: Single-point light-emitting Vs Multi-point light-emitting.

SMD: SMD packaging uses surface mount technology (SMT) to attach multiple discrete LED lamp beads to a PCB board to form a light source component for LED applications. It is a multi-point light source form.
COB: COB packaging is a high-efficiency integrated light source technology. It involves the placement of N chips on an inner substrate for packaging. Low-power chips are used to manufacture high-power LED chips, which results in a uniform small light-emitting surface.

4. Different heat dissipation effect

The COB light source uses small chips that are densely arranged to generate large and concentrated heat. The packaging material absorbs the heat and superimposes the heat inside the lamp body. However, it has a low thermal resistance heat dissipation method of “chip-solid glue-aluminum”, which guarantees heat dissipation. The SMD light source is limited by the package, and the heat dissipation needs to go through the steps of “chip-bonding glue-solder-solder-copper foil-insulating layer-aluminum”, which results in slightly higher thermal resistance.

But in the production of high-power lamps, SMD lamp beads are usually arranged and dispersed. This design provides a larger heat dissipation area and allows heat to conduct more easily. As a result, SMD lamps tend to have more stable temperatures than COB lamps, even during prolonged use. Therefore, for the temperature of the entire lamp, the general SMD solution is better than the COB solution.

5. Different application areas

Different types of light sources are better suited for different applications. For example, COB light sources are typically used in indoor lamps such as downlighters and spotlights, while SMD LED chips can be used in a wide variety of indoor and outdoor lamps. Each type of light source has its advantages and disadvantages, so it’;s important to choose the right one for your needs.

6. Different color rendering index (CRI)

As you may know, the color rendering index (CRI) of most SMD LED chips on the market is typically around 70-80. Some brands offer CRI90 options, such as Osram SMD2835. Most COB chips have a CRI above 90, even up to 97. This is also a good color rendering index. This is why indoor commercial lighting often chooses COB LED lamps for higher index requirements.